Vehicle headlamp including control to reduce illuminance of additional light distribution pattern and method of controlling the same

Abstract

A vehicle headlamp is provided. The vehicle headlamp includes a light source which is configured to form an additional light distribution pattern which is formed above a cut-off line of a low-beam mode light distribution pattern; a vehicle detection device which is configured to detect a presence of a front running vehicle; a road position detection device which is configured to detect an existing area of a road ahead; and a control unit. The control unit acquires information from the vehicle detection device and the road position detection device and, when the existing area includes a non-detectable area which is outside of a detectable area of the vehicle detection device, controls the light source to reduce an illuminance of the additional light distribution pattern.

Description

[0001]This application claims priority from Japanese Patent Application No. 2008-062677, filed on Mar. 12, 2008, the entire contents of which are hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Technical Field[0003]Devices, apparatuses, and methods consistent with the present disclosure relate to vehicle headlamps and, more particularly, to vehicle headlamps which control illuminance.[0004]2. Related Art[0005]In general, a vehicle headlamp provided on a vehicle can switch between a low-beam mode and a high-beam mode. The low-beam mode illuminates a place in the vicinity of a front running vehicle with a certain illuminance in order not to cause glare light to the front running vehicle. The front running vehicle includes an oncoming vehicle and / or a leading vehicle which travels in front of and in the same direction as the vehicle. The low-beam mode is mainly used when the vehicle runs in an urban district. On the other hand, the high-beam mode illuminates the fr...

AI Technical Summary

Benefits of technology

The present invention provides a vehicle headlamp that can secure visibility of a driver and reduce glare caused to a front running vehicle. The vehicle headlamp includes a light source that forms an additional light distribution pattern, a vehicle detection device that detects a presence of a front running vehicle, a road position detection device that detects an existing area of a road ahead, and a control unit that controls the light source based on information from the vehicle detection device and the road position detection device. When the existing area includes a non-detectable area that is outside of a detectable area of the vehicle detection device, the control unit reduces the illuminance of the additional light distribution pattern to improve visibility and reduce glare.

Problems solved by technology

Even though the high-beam mode is superior in visibility compared with the low-beam mode, there is a disadvantage in that the high-beam mode causes more glare light to a driver of a front running vehicle.

Accordingly, there is a disadvantage with the related art control technique in that a driver of the front running vehicle may falsely recognize that a following vehicle wants to pass.

However, there is a disadvantage in that when the following vehicle comes up on and encounters a front running vehicle before passing through a bent area of the curved road, the front running vehicle comes to be illuminated in the high-beam mode, causing increased glare to the front running vehicle.

In addition, even if the illumination state of the headlamp is switched based on information from a vehicle detection means instead of maintaining the illumination state of the headlamp, there is a disadvantages in that the front running vehicle may be already illuminated in the high-beam mode at a point of time when the front running vehicle is detected in front of the curved road, causing increased glare to the front running vehicle.

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